4 NM GATE DIELECTRICS PREPARED BY RTP LOW-PRESSURE OXIDATION IN O-2 AND N2O ATMOSPHERE

Extensive experimental results are reported about the rapid thermal O- 2 and N2O oxidation of silicon at pressures as low as 25 Torr. The dec rease of the oxidation rate in N2O is smaller than in O-2 atmosphere w ith decreasing pressure. Therefore, almost equal oxidation rates for t he oxidation in O-2 and N2O atmospheres were found at the lowest inves tigated pressure of 25 Torr. In addition, the low pressure oxides show better oxide homogeneities across the wafer; this is especially true for N2O oxides. Ultra-thin (down to 4 nm) dielectric films for applica tion in metal-oxide-semiconductor (MOS) devices have been fabricated a nd electrically characterized. The low pressure oxides exhibit higher charge to breakdown values and dielectric breakdown fields than atmosp heric pressure oxides. (C) 1998 Elsevier Science Ltd.